/***
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *    
 *    Linking this library statically or dynamically with other modules 
 *    is making a combined work based on this library. Thus, the terms and
 *    conditions of the GNU General Public License cover the whole
 *    combination.
 *    
 *    As a special exception, the copyright holders of this library give 
 *    you permission to link this library with independent modules to 
 *    produce an executable, regardless of the license terms of these 
 *    independent modules, and to copy and distribute the resulting 
 *    executable under terms of your choice, provided that you also meet, 
 *    for each linked independent module, the terms and conditions of the 
 *    license of that module.  An independent module is a module which 
 *    is not derived from or based on this library.  If you modify this 
 *    library, you may extend this exception to your version of the 
 *    library, but you are not obligated to do so.  If you do not wish 
 *    to do so, delete this exception statement from your version.
 *
 *    Project: www.simpledbm.org
 *    Author : Dibyendu Majumdar
 *    Email  : d dot majumdar at gmail dot com ignore
 */
package org.simpledbm.rss.api.tx;

import org.simpledbm.common.api.registry.Storable;
import org.simpledbm.rss.api.pm.PageId;
import org.simpledbm.rss.api.wal.Lsn;

/**
 * The Loggable interface and its sub-interfaces define the contract between the
 * Transaction Manager and its clients.
 * 
 * @author Dibyendu Majumdar
 * @since 23-Aug-2005
 * @see org.simpledbm.rss.api.tx.Redoable
 * @see org.simpledbm.rss.api.tx.Undoable
 * @see org.simpledbm.rss.api.tx.Compensation
 * @see org.simpledbm.rss.api.tx.NonTransactionRelatedOperation
 * @see org.simpledbm.rss.api.tx.PostCommitAction
 * @see org.simpledbm.rss.api.tx.ContainerDeleteOperation
 * @see org.simpledbm.rss.api.tx.LoggableFactory
 * @see org.simpledbm.rss.api.tx.BaseLoggable
 */
public interface Loggable extends Storable {

    /**
     * Gets the LSN associated with the log record.
     */
    public Lsn getLsn();

    /**
     * Sets the LSN for the log record.
     */
    public void setLsn(Lsn lsn);

    /**
     * Gets the ID of the TransactionalModule that generated this log record.
     * The TransactionalModule is responsible for redoing or undoing the effects
     * of this log record.
     * 
     * @see TransactionalModule
     */
    public int getModuleId();

    //    /**
    //     * Sets the ID of the TransactionalModule that generated this log record. 
    //     * The TransactionalModule is responsible for redoing or undoing the effects
    //     * of this log record.
    //     */
    //    public void setModuleId(int moduleId);

    /**
     * Gets the ID of the Page to which this log is related. Most log records
     * are related to individual pages. Sometimes a log record may be related to
     * more than one page, for example, a log record that implements
     * {@link MultiPageRedo} interface. Note that Dummy Compensation Log records
     * must return null from this method.
     */
    public PageId getPageId();

    /**
     * Sets the ID of the page for which this log record is being generated.
     * Also sets the type of the page. When the formatting of a new page is
     * being logged, the page type must be saved so that the correct type of
     * page can be fixed in the buffer pool during recovery.
     */
    public void setPageId(int pageType, PageId pageId);

    /**
     * When the formatting of a new page is being logged, the page type must be
     * saved so that the correct type of page can be fixed in the buffer pool
     * during recovery.
     */
    public int getPageType();

    /**
     * Points to the previous log record generated by the transaction.
     */
    public Lsn getPrevTrxLsn();

    /**
     * Points to the previous log record generated by the transaction.
     */
    public void setPrevTrxLsn(Lsn prevTrxLsn);

    /**
     * Transaction that created the log record. Automatically set when the log
     * record is inserted by the transaction. Note that for log records that are
     * not related to transactions, such as
     * {@link NonTransactionRelatedOperation}, the trxid.isNull() will evaluate
     * to true.
     */
    public TransactionId getTrxId();

    /**
     * Transaction that created the log record. Automatically set when the log
     * record is inserted by the transaction.
     */
    public void setTrxId(TransactionId trxId);
}
